Industrial plants, and especially coal-burning power plants, can be very dusty and dirty environments. Set in this environment, there can be numerous and complicated power cabling and other control and communication cabling systems. In order to protect those cabling systems from the dirty environment in which they are positioned, conduit is widely used as the pathway through which the cabling is installed. Periodically in this cabling and conduit system, there exist junction boxes for any one of numerous purposes. The connection of a conduit when mounted into a junction box is a specific area where dust especially can filter into the inside of a junction box. It is possible that dusty and dirty junction boxes, especially where explosive or flammable coal dust is involved, can result in a dangerous situation. And thus there is row a need to “retrofit” existing junction boxes with dust/water tight seals to comply with new industry requirements. Likewise, it is desirable that these junction boxes and conduit systems are also water-tight to protect the connections that are found in the junction box from unwanted condensation or liquids.
Traditionally, conventional locknuts are used to mechanically secure a conduit into a junction box. In this conventional system, the conduit has a threaded end that feeds into the junction box. Half of the locknut system is threaded onto the conduit and is outside the junction box. A second locknut is threaded onto the conduit on the inside of the junction box. The respective locknuts are then tightened onto each other to secure the conduit to the junction box. FIG. 1 illustrates a conduit 10 that is connected to a junction box 15. An outside locknut 20 is tightened using a second locknut (not shown) inside the junction box 15. The problem is that these conventional locknut systems are designed for mechanical securement, not sealing, and are therefore not effective at preventing dust and water from gaining access into the inside of a junction box.
It is conceivable that conventional, unitary locknut gasket systems can be engineered that have better sealing characteristics around this junction area between a conduit and a junction box. However, the installation of such a new locknut and gasket assembly requires that the cabling that travels through the conduit be disconnected so that a new locknut and gasket may be placed around the conduit and around the junction box opening. This is a substantial undertaking in time and mechanical labor and therefore there is a considerable expense for a retro-fit, one-piece conduit clamp seal.